Furnace



June 2, 1936. R. vom MATTEKOVICH 2042642 FURNACE Filed Feb. 18, 1931 Patentecl June 2, 1936 RATE NT G F'F l C E FURNACE Rudolf von Mattekovich, Resalic3, near. B'risbane, Queensland Australia Application lilabruary 18, 1931,;Se1ia1 N0. 516,772

13 Claims.

In a broad sense this invention relates to furnaces for the eosmbustion of solid wet fuels and/or solid wet or dry fuels possessing a high percentage of hydro-carbons generally, and particularly refers to improvements formingparts of the heiler furnace. Fuels hig-h in moisture include saw-dust, megass, tan bark anal the 1ike; fuels possessing a high percentage of hydrocarbons in addition to a high moisture content are principally lignites, while bituminous coals, and above all cotton hulls, and the like are representative of fuels conspicuous in their composition for volatile carbons.

Although my improvements may beseid to appertain more particularly to the combustion of 10W grade fuels, they are not necessarily limited thereto. The economic utilization oflow grade fuels depencls -entirely upon furnace efiiciency; excessive moisture a'nd/ora high percentage of hydrocarbons in fuel a1e factors adding materially to the cornplexity of the combustion problem. With such fuels there are four distinct phases in the process of combustion, namely (1)- pre-heating cf the fuel; (2) evaporation of the moisture and its conversion into superheated steam; (3) volatilization of hydro-carbonstheir heating to ignitionpoint together with the required quantity of air; and. (4) ignitionand combustion of both volatile and fixed carbons.

Phases (l), (2), and (3) are preparatory to phase (-4), and, their reacti0ns being endothermic, they should be allotteda separate space, preferably away from the boiler. Phase (4'), being exothermic should take place in theclosest proximity to the boiler; that is in the-combustion chamber of the main furnace.

The objeet of the invention is to provide means for adaption to existing furnaces for the more efiicient combustion of the above mentioned fuels, said means comprising apparatus whichmaybe attached to the present boiler furnace, wherein the fue1 is passed' throughthe initial or preparatory stages o1 phases of the combustion process prior to its entranceintothe main furnace room.

In order to make clear the character and import of my. inventiom reference will be made to the accompanying drawing wherein Figure 1 is a longitudinal sectional elevation of the apparatus as attachedto the boiler furnace;

Figures 2, 3, and 4 are respectively a side sectionalelevation, front elevation and horizontal cross sectional p1an of the vertical drying grates.

Figure;5is a view similar to Fig. 1 showing.

the modifiedform of construction in accordance with the present invention.

In Figure 1 the inventionis shown in its relation to a boiler furnace; which for convenience is illustrated in chai-n lines. and; Eincline respectively to the front and 110 the back, and at the1'r apex is mounted a, ga.ble C upon steel girders D. Two vertical drying grates B. and B" are suspended directly above the gable C,. and arexspaced apart from each other forming a passage for the fuel, which is fed inatthe top. Sliding down between the dryinggrates B and B the colum-n of fuel is split into two V01- umes When approachingthe apex of the gable C; and is. diverted into oppositadirections on to the respective fire gratesA and E.

The area of grate A is usua1lyless than that of. the main grate E. The relative surface area of these grates can be pre-determined once the anaiysis of the fuel to biaconsumed is known; with megass for instance containing fifty per cent ofmoisture anduhaving a gross thermal value 0i 37-80 B. t. u; per pound; a ratio ofone to six should be adopted; as it requires 630-B. t. u. or exactly one sixth ofthe total heat available 2 to evaporate. the contained water and. convert it into superheated steamof 600 F., the usual- Waste heat gas temperature.

The. column.of IueLfillingthe space between the vertical: grates. B and B, partitions off a portion at the frontiof the boiler furnacez forming a separate chamber not in communication with; the main furnace room. Thus the gases resulting from=. the fireon grate A cannot escape unless.they percolate through the column of fuel betweenthe vertica] grates Band B. The percolation of the gases is. promotect by the difference in the pressures in the respective fire rooms, that. is;.the-v pressure of the gases in the front fire room must exceed that in the back or main fire 1200m: by the pressure required to overcome the frictional-mesistance oiTered by the wa-1L of fue1.* The. depth and height of' the space betweemthe vertical. grates Band B for agiven rate -of consumption depend's en-ti'rely on the nature ofzthefuelto be burned. With fuels of 10W density such as. wood shavings, megass, 00tton, hulls and the like, an abundance of natural channels.reduces th'efriction of the gases passi-ng through:thecolumn of fuel, consequently the 50 spacea-between the verticalgrates can be deeper with low"density fuels. than with fuels of high density; such asbituminous mine slack.

The vertic'al 'g1ates B=and= B are preferably air=cooledbt grate=B beingexposed to greater heat may be water cooled instead, in whioh case it wi1lbe connected With the boi1er feed system or the boiler itself. These grates B and B ar e shown in detail in Figures 2, 3, and. 4, and consist of a number of pipes spaced. apart, the spacing being dependent upon the texture and divisibility of the fuel. Pipes F of grate B are respectively he1d. by their ends in top and. bottom headers G and H, and pipes F of grate B are held respectively in thetop rail K and bottom header I. The ends of pipes F in grate B open into headers G and H. The bottom ends of pipes F in grate B open into header I, but the top ends are placed in ho1es in rail K and held in suspension by caps which also close the ends. Air is de1ivered from a forced draught system into top header G, thence through pipes F of grate B, into bottom head.er I-I, thence into bottom header I, the ends 0f which are connected with the ends v of bottom header I-I by tubes J. From header I the now hot air enters the vertical pipes F of grate B to be blown out throughnumerous sma11 holes O which have been dril1ed in the outer side of the pipes F even1y distributecl ;fr0m the bottom ends to about half way up.

The bottom headers H and. I function also as fue1 ga tes between the drying grates B and B and fire grates A and. E, and to enable an unimpeded. ex1t for the fuel, and to progmssively advance its subsequent division into two columns, they are located at a distance above the apex of the gable C. The required thickness of the fuel bed. on grate E defines this distance.

Short pipes N extend through the header H and furnish the necessary adjustment to the gateway from the drying grates B and B to the fire grate A. These pipes N are closed at their ends and have ho1es drilled in them f0r forcibly distributing the hat air. The construction of vertical grates B and B enables easy removal and replaeement with the least possible interference With the working 0f the boiler. In the modified form of construction shown in Fig. 5, the feed water 1ine communicates with the lower header of grate B. Feed water flows through grate B in which it absorbs heat and. is then 1ed to the boiler P. When the grate B is water cooled, grate B alone is air cooled.

Since the wate-t vapor driven off from the fuel limits the performance of the combustion apparatus, provision is made in the case of very wet fuel for the separate discharge of the spent gases and the entrained vapors issuing from the upper part of the fuel column. This is effected by placing a partition L across the back compartment which prevents the mixture from following the path taken by the main fiue gases; vent M enabling an escape into the atmosphere.

The heat required to pass the fue1 through the initial stages of the combustion process is generated by burning a definite portion of the fuel on a separate grate (for example A). This grate A is separated from the main furnace grate E by the intervening vertical grates B and B which form the approach f01" the fuel to the fire grates A and E. The resulting gases are distributed over the whole face of the vertical grate B and a1e forced to traverse the column of fue1. which may be conveniently divided into two horizontal sections or zones to better perceive the effect cf the percolating gases upon the mass .of fue1. On its passage down between the drying grates B and. B the moving mass of fuel absorbs sensible heat from the percolating gases. In the upper Section or evaporation zone this heat supreaches the temperature at which carbonization is maintained. Emerging in common with the fire gases the hydro-carbons come int-o intimate contact with the heated air escaping through the perforations in the. pipes forming the back grate.

Thoroughly mixed With the air they travel then in the direction of the draught and are ignited and burned while passing over the incandescent fue1 bed on the main grate. Leaving the drying grates B and B the fuel is passed onto the respective fire grates A and E. It is then in such a state that it will ignite and burn readily producing a high and equable furnace temperature.

The arrangement of placing a partition, such as L, horizontally across the back compartment and immediately above the 1ower section or earbonization zone, recommends itself where no useful purpose can be served by drawing a mixture of incombustible gases and water vapors of a. temperature at o1 be1ow that of the exit waste gases through the boiler furnace. With extremely wet fue1s it is a decided advantage t0 e1iminate so lauge a'volume of inert gases and vapors thus increasing the furnace temperature, and With it the rate and completeness of combustion, which in turn 1eads to a higher furnaceboiler-efficiency.

The apparatus in itself is total1y independent and adapted to be used in conjunction with any type or types of fire-grates, also permitting the application of any known systems of controllable air supply.

As a coro1lary to the foregoing, and in a broad sense as implied on the first page 0f the specification, it will be seen that my invention consists essentially of the practical arrangement of improvements as part of the boiler furnace, repre senting apparatus wherein the fuel passes through the preparatory stages of combustlon process enabling the continuous generation of definite, pre-determined volumes of high temperature gases in a separate chamber, their concentration over the whole face of the fue1 mass and their subsequent penetration there through v resulting in the delivery of de-hydrated and/01' carbonized fuel in such an advanced state 01 preparedness on to the fire grate as to insre perfect and complete combustion.

Although the invention has been described and illustrated in relation to the economic cornbus-. tion of fue1s as before mentioned, it will be understood that the invention may be applied to town refuse destructors and the like.

I claim:

1. In furnaces of the class described, a. main fire-grate, a subsidiary fire-grate, a v8rtical fuel delivery chute between said main and subsidiary firegrates said ahnte consisting of water and air tubes the water tubes being nearest to the subsidiary fire-grate and in communication and in series with the boiler, the air tubes beim:

feed wziter to the heiler is pats'sed -and the other ahnte Wall being aonstrnated of tubes throng'h Which combnstion snppo'rting a;i'r is paSsed for pt-eheating, and means for cansi'ng prodncts of 'combnstion from seid subsidiary grate to pass through said ahnte to pfetreat the fuel therein.

3. In a boiler heating fnrna'ce '0f the dass desaiibed, a. main fir'e-grate anda. snbsidiary firegr'a;te, 'sa.id fire-grates being horizontally spaaed -a.nd separated by inalined fuel delivery s'heds, sind fnrnaae having an ontlet for the hat gasas positioned over the mein fire grate, a, vertical fnel delivery ahnte for snpplying fuel to both of sa;id fire grates and positioned between said horizontally spaced grates, seid ahnte being f0rmed of two spaced Walls extendingacross said fnrnaae, one of said Walls being formed of a "plurality of spaaed tnbes having one end canneted to the boiler feed and the 0ther end can- -nected to a. snpply of feed water, the other cf said ahnte Walls being formed of tubes, mea.ns

for passing 001d combnstion snpporting air there- -through said ahnte being positioned so that prodncts of combnstion from the snbsidiary grate must pass throngh the aolumn 015 fuel contained therein in fiowing to said ontlet.

4. In a. boiler heating fnrnace of the dass de- -saribed a. main fire-grate and a. subsidiary fi1e rgiate, saidfire-grates being horizontally spa.aed

anclseparated by inclined fuel delivery sheds, said fnrnace having an entlet for the hat gases 0sitioned over the m'a-in fire-grate, a. vertical fuel delivery ahnte for supplying fuel to both -of sa'icl fire grates a.nd positioned. between said horizontally spaced grates, said ahnte being formed of tw0 spaaed Walls extending across said furna;ce, one of said Walls being formed of a plurality of spaced tubes having one end conneated to the boiler feed and the other end cannected to a supply of feed water, the other of said ahnte Walls being formed of tubes, mea.ns for passing cold combnstion snpporting air therethrongh, said. ahnte being positioned so that prodncts of combnstion from the snbsidiary grate must pass throngh the aolumn of fuel contained therein in flowing to said ontlet, and the ahnte Wall throngh which air is passed being provided with a plurality of air ontlets for snpplying aombnstion snpporting air to the coutents of the fnrnace.

5. In a boiler heating furnace of the dass clescribed, a main fire-grate, an outlet flue above said main grate, an inclined fuel delivery shed for feeding fuel to said main grate, a. vertiaal fuel delivery ahnte for snpplying fuel to said shed, seid ahnte being removed from seid grate and aomprising a pa.ir of spaced Walls, one of said Walls being formed. of wa.ter tnbes counected between a feed water snpply and the feed water in]et to the boi1er, the other ahnte Wall being formed of air tubes, means for passing air throngh said tubes, a snbsidiary firG-grate positioned below and horizontally spaced from said ahnte so that the ahnte is between the sub- -sidiary grate and the ontlet flue, andan ihaIi-ned shed for feeding a, portion of the fuel in the ahnte to the subsidiary grate.

'6. Ina boiler hea.ting furnace cf the dass desaribed, a -mtin fire-grate, an ontlet flue aboVe Saidmain -gr ate an inalined fuel delivery shed for feeding fuel to said main grate, a vertiaal fneldelivery ahnte for snpplying fuel to said. shed,

seid ahnte being removed from seid grate and aomprisihg a pair of spaced Walls, oneofsaid Walls being formed. of vvater tnbes C0nneated between a fee'd water snpply andth'e feed water inlet 'to the boiler, the other ahnte Wall being forme'd of air tubes, means for passing air throngh said tubes, a. snbsidiary fire-grate positioned below end horizontally spaced from said ahnte so that the ahnte is betvveen the snbsidiary grate and the ontlet flue, end an inclined shed for feeding a portion of the fuel in the ahnte to the snbsidiary grate the ahnte wa.1l throngh which air is passed being provid'ed With a. plnmlity of air ontlets for supplying combnstion supporting air to the aontents of the furnace.

7. In a boiler heating furnace of the dass desaribed, a. main fire-grate and a snbsidiary firegrate, saicl fire-grates being horizontally spaced anti separated by inclined fuel delivery sheds, sa.id fnrnace having an ontlet for the hot gaseS positioned over the main fire grate, a vertical fuel delivery ahnte for supplying fuel to both of said fire gra.tes anal positioned between said horizontally spaaed grates, said ahnte being formed of two spaaed Walls extending acrosssaid fnrnace, one of said wal1s being formed' of a. plnrality of spaaed tnbes having one end aonnected to the boiler feed and the other end C011- neated to a, snpply of feed water, the other of s'aid ahnte Walls being formed of tubes, means for passing aold aombnstian snpporting air therethrongh said ahnte being positioned so that prodncts of aombnstion from the snbsidiarY grate mnst pass throngh the aolumn of fuel cantained therein in flowing to seid ontlet and the wa1l of said ahnte throngh whiah water is passed being positioned adjacent the subsidia.ry firegra.te so that it is first snbjected to the hot produats 01 aombustion flowing from the subsidiar'y grate.

8. In a. heiler hea.ting fnrnace of the dass described, a. mein fire-grate, an ontlet flue above said ma.in gra.te, an inalined fuel delivery shed for feeding fuel to said ma.in grate, a. vertica1 fuel delivery ahnte for supplying fuel to said shed, said ahnte being removed from said grate and aomprising a. pair of spaced Walls, one 01" said walls being formed of water tnbes connected between a. feed wa.ter snpply and the feed water inlet to the boiler, the other ahnte Wall being fo-rmed of air tubes, means for passing air throngh sa.id tubes, a. snbsidiary fire-grate positioned below and horizontally spaced from seid ahnte so tha.t the ahnte is between the snbsidiary grate a.nd the ontlet flue, end an inclined shed for feeding a portion of the fuel in the ahnte to the snbsidiary grate, the Wall of said ahnte throngh which wa.ter is adjacent the subsidiary fire-grate so that it is first snbjeated to the hat products of aombustion flowing from the snbsidiary grate.

9. In a. heiler heating fnrnace of the dass desaribed, a. main fire-grate and a snbsidiary firegrate, said fire-grates being horizontally spaced end separated by inclined fuel delivery sheds, said fnrna.ae having an outlet for the hot gases positioned over the mein fire-grate, a vertical passed being positioned fue1 delivery chute for supplying fuel to both of said fire-grates and positioned between said horizontally spaced grates, seid ahnte being formed 0f two spaced Walls extending across said furnace, one of said Walls being formed of a plurality of spaced vertical tubes communicating with upper and lower headers, the other of said Walls being formed of a plurality of spaced vertical perforated tubes having their upper ends closed and communicating at their lower ends with a header communicating with the lower header of the first-recited tubes, and means for passing air into said upper header to fiow down through the tubes connected therewith, through said. lower headers, up into the perforated tubes and through the perforations into the furnace.

10. In a, boiler heating furnace of the c1ass described, a main fire-grate and a. subsidiary firegrate, said fire-grates being horizontally spaced and separated by inclined fue1 delivery sheds, gaid furnace having an outlet for the hol: gases positioned over the main fire grate, a vertical fue1 delivery chute for supplying fuel to both of said fire grates and positioned 'between said horizontally spaced grates, said ahnte being formed of two spaced Walls extending across said furnace, one of said walls being formed of a. plurality of spaced vertical tubes communicating with upper am]. lower headers, the other of said wa.1ls being formed cf a plurality of spaced vertical perforated tubes ha.ving their upper ends closed and communicating at their lower endS with a header communicating With the lower header of the first recited tubes, means for passing air into said upper header to f10w down through the tubes connecoed therewith, through said, lower headers, up into the perforated tubes and through the perforations into the furnace, and short perforated tubes depending from the lower header of'said first-recited tubes to distribute combustion air in the. vicinity 0f said subsidiary fire-grate.

11. In a heiler heating furnace of the dass de scribed, a main fire-grate and a subsidiary firegrate, said fire-grates being horizontally spaced and separated by inclined fue1 delivery sheds, said furnace having an outlet for the hob gases positioned over the main fire-grate, a. vertical tue] delivery chute for supplying fuel toboth of said fire-grates and positioned between said. horizontally spaced grates; said chute being formed of two spaced Walls extending across said furnace, one of said Walls being formed. 'of a plurality of spaced vertical tubes communicating with upper and lower headers, the other of said Walls being formed of a plurality of spaced vertical perforated tubes having their upper 'ends closed and communicating at their lower ends With a header, and means f or passing air through the tubes of at least one of the Walls of said fue1 delivery ahnte.

12. In a, heiler heating furnace of the dass desoribed, a, main fire-grate and a subsidiary firegrate, said fire-grates being horizontally spaced and separated by inclined fuel delivery sheds, said furnace having an outlet for the hot gases positioned over the main fire-grate, a vertical fuel delivery ahnte for supplying fuel 150 both of said fire-grates and positioned between said horizontally spaced grates, said chute being formed of two spaced Walls extending across said furnace, one cf said Walls being formed 0f a. plurality of spaced vertical tubes communicating With upper and lower headers and adapted to contain a 'cooling medium, the otherof said Walls being formed of a plurality of spaced vertica1 perforated tubes having their upperends closed and communicating at their lower ends with a header, and means for passing air through the perforated tubes and through the perforations into the furnace.

13. In a boi1er heating furnace 0f the dass described, a main fire-grate and a, subsidiary firegrate, a vertically arranged fuel delivery chute positioned to de1iver fuel in determined proportions o0 both of said fire-grates, said delivery chute comprising a, pair of spaced walls extending across said furnace, one cf said chute wa11s being constructed of tubes thr0ugh which water is passed the boiler and the other chute wall being constructed of tubes through which a cooling medium is passed and means for causing products of combustion from said subsidiary grate pass through said chute 130 pretreat the fue1 therein.

RUDOLF VON MATTEKOVICH. 

